Apparatus for forming an impregnated paper web with corrugations or pleats

ABSTRACT

An apparatus for continuously forming an impregnated paper web with corrugations or pleats extending diagonally to the edges of the web in an elongated form movable along a straight path and formed with grooves extending in the same diagonal direction and entered by projections from a forming head rotatable about an axis parallel to said diagonal grooves, said projections being disposed in such a manner that at least one projection always retains a corrugation or pleat formed by the same in the paper web pressed against the form so as to prevent a sliding back movement of the web during formation of the next following corrugation.

Aug. 8, 1972 c. s. MUNTERS 3,682,747

- APPARATUS FOR FORMING AN IMPREGNATED PAPER WEB WITH CORRUGATIONS OR PLEATS 3 Sheets-Sheet 1 Filed larch 10, 1970 Carl G-wr -Ovnfi6 YM Aug. 8, 1972 c, MUNTERS 3,682,747

APPARATUS FOR FORMING AN IMPREGNATED PAPER WEB WITH CORRUGATIONS OR PLEATS Filed March 10, 1970- 5 Sheets-Sheet 2 R, 3 m N L K Flg 4 Heb INVENTOR CARL GEORG MUNTERS .8, 1972 c G. MUNTERS 3.

APPARATUS FOR FORMING AN IMPREGNATED PAPER WEB WITH CORRUGATIONS OR PLEATS Flled March 10, 1970 3 Sheets-Sheet 3 Cl?! Gioj fl nk- QWQA/LW/ 3,682,747 Patented Aug. 8, 1972 3,682,747 APPARATUS FOR FORMING AN IMPREGNATED PAPER WEB WITH CORRUGATIONS OR PLEATS Carl Georg Munters, Stocksund, Sweden, assrgnor to Carl Munters & Co., Sollentuna, Sweden Filed Mar. 10, 1970, Ser. No. 18,097

Claims priority, application Sweden, Mar. 11, 1969,

Int. ci. B31f 1/00 [1.8. Cl. 156459 4 Claims ABSTRACT on THE DISCLOSURE An apparatus for continuously forming an impregnated paper web with corrugations or pleats extending diagonally to the edges of the web in an elongated form movable along a straight path and formed with grooves extending in the same diagonal direction and entered by projections from a forming head rotatable about an axis parallel to said diagonal grooves, said projectionsbe ng disposed in such a manner that at least one pro ection always retains :a corrugation or pleat formed by the same in the paper Web pressed against the form so as to prevent a sliding back movement of the web during formation of the next following corrugation.

BACKGROUND OF THE INVENTION 'changerbodies for two fluids, of which one may be a liquid, such asvwater, and the other a gas, such as air. Examples of such fields are cooling towers, moistening devicesand the like. .Web of paper is understood to mean that the material is fibrous such as made of asbestos or cellulose fibres.

Material of this kind possesses in. itself very slight stability and loses much of its strength in wet condition. Therefore, it has already been proposed h'eretobefore to increase the wet strength by impregnation with a substance which is insoluble in the liquid streaming through the contact body. As example of such substances may be mentioned resins, which in the primary instance may consist of, or contain, phenol or melamine. The addition of this substance is usually effected by wetting the paper with a liquid containing the impregnating agent or agents for which reason the paper sheets during this process acquire considerably reduced durability. Furthermore, the material of which the sheets are composed, is characterized by its very slight surface extensibility and therefore, cannot be stretched at all or to any appreciable degree without becoming damaged.

In the contact body all of the sheets may be corrugated in which case the diagonally extending corrugations cross one another in adjoining sheets. This requires that the sheets must be produced in the corrugated shape as units which are self-sustaining before they are stacked together in cross-wise relationship and, if desired, are bonded together at the points of contact by means of an adhesive.

' These conditions create specific requirements on the manufacture of the corrugated sheets, in particular if this manufacture shall be conducted in an efiicient manner and at a low cost.

OBJECTS OF THE INVENTION With these premises as a starting point, one main object of the invention is to provide a forming head which in cooperation with the form produces corrugations without subjecting the web of paper to disturbing strains or sliding movements relative to the form so that the formed corrugations acquire the predetermined height and profile within close tolerances.

A further object is to provide a forming head which renders possible high speed of the moving paper web and therewith high capacity of the apparatus.

SUMMARY OF THE INVENTION The aforementioned objects and other advantages inherent in the invention are obtained by providing projections which are spaced radially about the rotary forming head and are movable transversally to the plane of the form in such a manner that at least one projection always retains a corrugation formed by the same and presses it against the form. According to a particular suitable embodiment the forming head as a unit, i.e. including the projections, is disposed movably transversally to the plane of the form.

Due to the feature that the projections or the battens move in a plane perpendicular to the axis of rotation of the forming head which axis in turn forms an oblique angle to the direction of movement of the paper web and the straight portion of the elongated form, there is produced by the forming of a corrugation of the paper web not only a sliding movement between the web and that ridge of the form over which the corrugation is conveyed down into the groove of the form, but also a sliding movement having an axial component between the projection of the forming head and the paper web. Hitherto it has been the general belief that in particular the last-mentioned sliding'movement tends to destroy the paper web. However, the belief has proved to have been wrong. The explanation for this surprising discovery resides in the movement of the forming head away from, and towards, the travelling portion of the form so that the finally formed corrugation produced by at least one projection always retains an unchanged position in the groove of the form.

Further objects and advantages of the invention will become apparent from the following description, considered in connection with the accompanying drawings, which form part of this specification.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a forming head constructed in accordance with the invention and a portion of the elongated form cooperating with the same.

FIG. 2 is a sectional view following line II-II of FIG. 1 of the forming head and the form, impregnating and drying means for the paper web being also indicated, though in a reduced scale.

h P56 3 is a side view in a larger scale of the forming FIGS. 4 and 5 show diagrammatically the forming of a paper web with corrugations viewed at two different positions relative one another of the form and the battens or vanes of the forming head.

DETAILED DESCRIPTION Referring to the drawings, a forming head is generally denoted 10 and an endless forming belt the represented portion of which is denoted 12. The endless belt may be composed of a series of plates or sheet metal parts 14 arranged in sequence one behind the other and formed with mutually parallel corrugations or grooves 16 extendmg diagonally over each plate 14. The endless belt travels relatively to a fixed frame 18 in the direction indicated in FIGS. .1 and 2. by arrow 20.'If the forming belt is composed of plates 14 of the type just described it can cooperate with a driving mechanism in accordance with the disclosure in the -U.S. Pat. No. 3,470,280 to provide a closed circuit, the upper horizontalv portion of which is represented in the figures of this application and denoted 12. r

In the illustrated embodiment the forming head.10 includes a cylinder 22,which about its circumference has radially projecting battens or vanes 24 which may consist of a non-metallic material such as polytetrafluoroethylene or some other plastic material. The battens or vanes are equally, distributed about the circumference of the cylinder 22 and are in the embodiment rigidly secured thereon e.g. by means of L-shaped holders 26. The forming head and the battens 24 are positioned diagonally in relation to the direction 20 of travel of the belt portion 12 in such a manner that they are in parallel with the 1ongitudi'nal extension of the grooves 16.. The battens 24 are spaced from one another at their'outer periphery a distance equal to the distance between the bottoms of two adjacent grooves.

The forming head is mounted at each of its ends in links 30 by means of a journal 28, which links in turn by means of taps 3.2 are mounted in brackets 34 fixedly connected with the frame 1 8. In the operative position of the forminghead 10, the journals 28 and the taps 32 are located at least at approximately the same level about the upper portion 12 of the forming belt. In this way, the battens 24 of the forming head 10 can be swung upwards and downwards along a path which with a little amplitude of movement is approximately straight and which is perpendicular to the plane of the underlying forming belt portion 12. I

The forming head 10 maybe kept pressed againstthe forming belt portion in addition to its own-weight by means of a spring member 36 provided on.one or both sides of the forming belt portion. The downward turn.-

ing of the forming head 10 in direction towards the forming belt portion may be limited by means of setting-screws 38, one of which is screwed through a support 40 carried by the frame 18 and located at each end of the forming head. The setting screw can be adjusted and locked at various positions by means of a nut 42.

FIG. 2 shows the means for impregnation of the paper web and driving thereof followed by the pleating or corrugating operation. From a storage roll 44 consisting of e.g. v asbestos paper which is mounted on a shaft 46 in a frame impregnating liquid is of such a kind that after heat treatment it imparts required mechanical strength to theasbestos sheet material both in dry and in wet condition and also makes it resistant to attacks of various nature onthe material. This liquid may consist of a solvent and one or more impregnating agents dissolved therein. As example in this respect may be mentioned melamine dissolved in water, said liquid, if desired, containing a minor quantity of alcohol and a catalyst to accelerate the conversion of the melamine into solid, water-insoluble form.

The web 50 of asbestos, which suitably hasa thickness of about one or some tenth of a millimeter is conducted after impregnation between the forming head 10 and the forming belt portion 12 at a predetermined oblique angle as is described in greater detail in the abovementioned patent, so that the direction of movement of the corrugated paper web becomes parallel withthe direction 2t) of movement of the forming belt portion. The forminghead '10 does not necessarily have its own driving means, but may be carried along in its rotational movement about the journals 28 by the plates 14 passing underneat'hthe same.

OPERATION FIGS. 4 and 5 show diagrammaticallythree battens 24a, 24b, 24c, which rotate about the axis 24 of rotation of the forming head in the direction indicated by the arrow 25. i

In the position illustrated in FIG. 4, a batten "24a'has during the rotation oftheforrriing head reached a' position' directly below the axis 27 of rotation of the forming head. The batten 24a has formed a corrugation in the paper web 50 and bears under the action exerted by the spring member 36 against: the bottom of that groove 16a with which the batten .-24a cooperates. By the batten 24a the forming head has been raised upwards againstthe action of the spring member 36 so that the batten 24a can pass between the forming h ead and the forming belt portion. At the same time the next vfollowing batten 24b has -commenced to force a new corrugation formed in the paper web 50 down into the next following grooye 16b. During the, continued synchronized movementof the advancing belt. portion 12 and the forming head,10, the batten 24b moves downwards towards the bottom of the groove. 16b. The batten 24a, however, is during the continued rotation of the forming head imparted an up wards directed component of movement relative to the. axis of rotation 27 of the forming head, but due to,,the. ,mov

able mounting of the forming head this head moves downwards so .that said batten remains incontactwith the paper web which thus continuously abuts :ag ainstthe underlying groove 16a. While thus the batten 24b draws a new corrugation of the paper web down to the bottom of its associatedgroove 16b, the corrugation previously formed by the batten 24a is retained so that the paper web cannot slide backwards whereby the corrugation might be destroyed. a V

In a slightly later position of the forming head and the forming belt portion during their synchronized movements,-both battens 24a and 24b are positioned, as shown in FIG. 5, symmetrically relatively to a'vertical plane through the shaft 27 of the forming head and thus are bothactive in retaining its associated paper corrugation pressed against the form grooves 16a and 16b, respectively. When the batten 24a thereupon leaves the paper web, the contact pressure against the'forniing belt portionis taken over by the batten 24b while the forming head anew performs an upwards movement while the next following batten 24c draws down the corrugation formed by it, etc.

As will become evident from the foregoing, only one corrugation of the paper web ata time is drawn down into its' associated groove under sliding friction against the nearest ridge projection of the form. Hereby the strain on the wet paper web is reduced to a minimum. As an upper limit it can be established that at the utmost two battens or projections shall be active simultaneously for drawing down corrugations into the grooves of the forming belt portion. Decisive for the number of corrugations formed simultaneously is the ratio of the magnitude of the radii of the battens at their outer edges to the dimensions of the corrugations'in the paper web i.e. the height of the corrugations which may range between 15 mm. to 25 mm. to the length of the corrugation. These dimensions are in turn determined by the shape of the grooves of the form. I In other words, the length of the battens and .the spacing therebetween must be adjusted in such a-manner that the edge of the batten 240 in FIG. 5 facing'the paper web in the position when the batten 24b has reached the bottommust not havev reached full contact with the paper web and in e'very case must notbe positioned substantially lower than the ridges of the forming belt portion. It is understood that dueto the continuous pressure ofithe battens against the forming belt portion '12 which,

venience be driven by the forming belt which feature substantially simplifies the structure.

The finished corrugations can be retained in the grooves of the form by means of reduced pressure produced in a space defined by a hood 58 at the underside of the forming belt portion 12. The vacuum space is through a conduit '60 in connection with a suction side of a fan or the like (not shown). The plates 14 are perforated so that the reduced pressure in the space 58 can be propagated to the paper web. This web can finally be dried or hardened while still resting in the grooves of the forming belt portion 12 by supply of heat such as radiated heat from an electric heating furnace 62. This device as Well as means for removal of the finally corrugated paper web from the forming belt and its severing into individual sheets is described e.g. in the patent specification referred to above.

The battens or vanes 24 are preferably stitf so that they will not or only insignificantly flex laterally when they form the corrugations of the paper web.

It is conceivable that the battens or vanes 24 may be individually resilient either by themselves or by means of a specific resilient mounting on the cylindrical portion of the forming head so that they can move radially relative to said part. In such a structure the forming head may be stationary.

While one more or less specific embodiment of the invention has been shown and described it is to be understood that this is for purpose of illustration only, and that the invention is not to be limited thereby, but its scope is to be determined by the appended claims.

What is claimed is:

1. Apparatus for producing a corrugated sheet from a web of deformable material comprising:

(a) a molding belt movable in a longitudinal direction while supporting the web being advanced thereby;

(b) said molding belt having a series of grooves extending across the belt diagonally to the direction of the longitudinal direction thereof;

() a cylindrical molding head mounted above said molding belt to rotate about an axis parallel to the diagonally extending grooves;

(d) a plurality of members extending radially from and peripherally spaced about said molding head;

(e) said members having such extension in a radial direction as to engage the web and depress it into said groove as the belt is advanced and to exert pressure on said molding head;

(f) means providing resilient displacement of said members with respect to said belt when the Web is depressed into the groove so as to retain the corrugated web in forced contact therein for a limited longitudinal movement of the web by said molding belt until a succeeding member has formed a successive corrugation.

2. Apparatus according to claim 1 in which the web Engaging members are displaced jointly with the molding ead.

3. Apparatus according to claim 1 in which the molding head is resiliently mounted.

4. Apparatus according to claim 1 having means for impregnating the web with a liquid solution comprising a trough mounted adjacent the feeding end of the belt for immersing the web therein.

References Cited UNITED STATES PATENTS 3,470,280 9/1969 Munters et al 264- X 2,110,683 3/ 1938 Schiiler l56206 X 1,796,542 3/1931 Schoo 156-205 X 3,396,445 8/1968 Hopkins et al. 281.8 X 1,488,504 4/1924 Keyes 15 6-206 3,470,053 9/ 1969 Rule l56--207 2,193,052 3/1940 Atwater 156-205 690,713 I/ 1902 Ferres l8----19 A FOREIGN PATENTS 104,202 4/ 1942 Sweden.

BENJAMIN A. BORCHELT, Primary Examiner H. T. TUDOR, Assistant Examiner US. Cl. X.R. 

